The present invention concerns a transformation station for a packaging production machine, that is a machine designed for the manufacture of folding boxes from a material in a strip or in sheets.
Such packaging production machines comprise several successive transformation stations, for example, a feed station, followed by one or more printing stations, where necessary a scoring station, an embossing station, a rotary blanking station, a waste ejection station, and finally a folding box blank receiving station. Since this type of machine has a modular design, it is possible that, in a preferred configuration, a machine comprises, in addition to the feed station, the printing and blank receiving stations, only one embossing station followed by a rotary blanking station and by a waste ejection station.
The strips or sheets, for example strips or sheets of cardboard, may usually contain over their width several identical box preforms or blanks which each represent the shape and the folded-out surface area of the manufactured packaging. The number of preforms that may thus be placed side by side naturally depends on the width of the medium being worked, but also on the maximum format accepted by the machine and the size of the box blanks. Usually, the box preforms or blanks are placed at either side of the theoretical median axis of the strips or sheets being worked by the machine. The various stations of the machine are all fitted with specific tools, preferably with rotary printing, blanking, embossing and scoring tools and tools for ejecting the waste resulting from the blanking operations, whose dimensions correspond to the width of the strips or sheets being worked. For the rotary printing tools, the change of width of the strips poses no particular problems because it is sufficient to mount an appropriate die on the die-carrier cylinder. On the other hand, for the rotary blanking, embossing, scoring and ejection tools, which are mounted in cassettes, an example of which is described in patent FR 2 819 744 B1, this poses a problem associated with the construction of these cassettes. In practice, these cassettes may originate from several manufacturers chosen by the packaging producer according, for example, to advantageous cost or more advantageous wear performance. To adapt for use of cassettes from different manufacturers, a cassette adapter is used to make it possible to insert cassettes of any origin, such as the one described in patent application EP 1 331 054 A3. Currently, for each strip or sheet width, tool-carrier cassettes of corresponding width must be used. The width dimensions of a strip of cardboard, for example, may vary within a range lying between 325 and 850 mm. Usually, the most common widths used by the manufacturers of folding boxes are 550, 670, 820 and 850 mm, widths defined by the width dimensions of the box blanks to be worked. The packaging manufacturer faced with the use of several widths of cardboard strips must choose a solution, which is very costly and requires the use of considerable space in a carton production plant, and which consists in using several machines with different strip throat widths.
At the present time in the inventor's knowledge of the prior art in this field, there is no other solution making it possible to alleviate the disadvantages that unavoidably occur when using variable strip widths.